Galvanomagnetic devices

Galvanomagnetic properties in the form of Hall and magnetoresistance effects have been rescued from relative obscurity by the successful emergence of sophisticated semiconductor materials and techniques. Long a part of the standard curriculum, these phenomena have unleashed a plethora of useful electromagnetic devices by the adroit application of relatively simple principles. Although solid-state research has certainly been enhanced by the electron-mobility and band-structure analysis capability of galvanomagnetic effects, who would have thought that potentiometers, choppers, gyrators, and push buttons could find new substance with long-established phenomena?